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Abstract
Objectives Since 2018, Sexual Health London (SHL) has provided remote sexually transmitted infection (STI) testing services to London residents over 16 years of age. SHL was an asymptomatic screening service. In 2020, SHL widened access to non-urgent symptomatic testing. We undertook a 4-year evaluation on the uptake of SHL’s online testing pathway and outcomes, including the association of positive chlamydia and gonorrhoea nucleic acid amplification test (NAAT) outcomes with user demographics and user utility.
Methods This is a retrospective data analysis of routine SHL clinical data from 8 January 2018 to 31 March 2022 of all STI test kit orders, focusing on HIV, chlamydia and gonorrhoea outcomes. Descriptive analysis on uptake of each stage of SHL’s clinical care pathway is provided, including HIV testing outcomes. Binary logistic regression was used to examine the association between SHL user-completed online consultation information, SHL uptake and chlamydia and gonorrhoea NAAT results (negative or positive).
Results During the evaluation period, there were 1 476 187 orders made by 670 293 unique users. The return rate for chlamydia and gonorrhoea NAATs was 79.5% and 67.6% for HIV blood samples. The positivity rate from sufficient samples was 4.5% for chlamydia, 1.6% for gonorrhoea and 0.3% reactivity for HIV. There were increased odds of a positive chlamydia and gonorrhoea NAAT result in non-cisgender women, those with a high number of STI orders, non-UK born and those who collected an STI test kit from a clinic-based service.
Conclusions To date, this is the largest number of orders in an evaluation of online postal sexual health infection testing in the UK, and highest return rate of samples, suggesting acceptability of SHL for STI testing. Positivity rates for chlamydia and gonorrhoea NAAT tests are lower than national figures, which may reflect asymptomatic screening prior to 2020 and testing of non-urgent symptoms since 2020.
- delivery of health care
- HIV
- sexual health
Data availability statement
Data may be obtained from a third party and are not publicly available. Data were provided by Preventx with permission from SHL’s data controller.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Online postal self-sampling (OPSS) services have been increasingly commissioned in the UK over the last 10 years with evaluation data focusing on return rate of samples, over relatively short evaluation periods.
As OPSS become embedded into sexual health services in the UK, more evaluation data are needed on bloodborne virus outcomes, clinical care continuum uptake and sexually transmitted infection (STI) treatment uptake.
We present the largest UK OPSS evaluation for STI testing, which includes 1 476 187 STI completed test kit orders from 670 293 unique users, as well as data on treatment and HIV testing outcomes.
WHAT THIS STUDY ADDS
We found an increased likelihood of positive nucleic acid amplification test results for chlamydia and gonorrhoea in all gender groups compared with cisgender women, and we are the first to report STI associations in non-binary groups.
Chlamydia test positivity among those aged 16–20 years was 9.7%, reflecting national chlamydia screening programme of 10% in those aged 15–24 years.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
There needs to be further work to understand uptake of HIV testing of unique users, with triangulation of data between services.
To support future evaluation work, standardised data definitions would support the novel aspects of OPSS compared with clinic-based services.
Introduction
From 2021 to 2022, testing for sexually transmitted infections (STIs) in London increased by 16% and new STI diagnoses rose by 21%.1 Nationally, the proportion of consultations completed via online postal self-sampling (OPSS) services compared with face-to-face or phone consultations increased from 21% in 2019 to 53% in 2022.1 Numbers of OPSS services commissioned across the UK by local authorities (LA) and the National Health Service (NHS) have increased over the last 10 years.2–4 However, the literature reports OPSS service evaluations in the UK over short time periods (<1 year).2–5 As OPSS has become increasingly embedded into sexual health services (representing half of sexual health consultations in 2022) and STI rates have risen, more evaluation data on their performance and utility are required.
Evaluation data from UK-based OPSS services have focused on return rates and characteristics of users. A recent scoping review of OPSS services found variable return rates of samples (ranging from 48.3% to 78.4%), but there are limited data on bloodborne virus (BBV) outcomes and treatment uptake.5 Furthermore, there are little data on OPSS users who have never used clinic-based sexual health services. Understanding how online service users engage with OPSS is necessary for future service planning.
We address these gaps by examining the uptake of each stage of the OPSS continuum for London’s largest OPSS provider, Sexual Health London (SHL), and providing STI testing outcomes. SHL is a collaboration of services, involving Preventx, Chelsea and Westminster NHS Trust and LloydsPharmacy Online Doctor (LPOD), commissioned by LA. SHL operates alongside clinic-based sexual health services to provide sexual health testing and remote chlamydia treatment, with signposting and linkages to other services where necessary.6
Setting
SHL provides Chlamydia trachomatis (chlamydia), Neisseria gonorrhoea (gonorrhoea), HIV and Treponema pallidum (syphilis) testing to all users, and hepatitis B and C testing based on risk, to London residents aged 16 years or older.
Users register with SHL via a webpage. To obtain an STI test kit, the user completes an online consultation form covering demographics, sexual history, sexual behaviour, lifestyle and safeguarding questions. Consultation forms determine appropriateness for remote STI testing pathways. For example, if users had symptoms prior to the COVID-19 pandemic, they were redirected to clinic-based services. Once the user has completed the consultation form, they order an STI test kit and can collect it from a clinic-based sexual health service (a ‘smartkit’) or request postal delivery (postal kit).
The SHL consultation form and clinical service have evolved during the analysis period. Major changes were introduced in April 2019, March 2020 and March 2021 and details related to this analysis are in table 1 and the online supplemental appendix.
Supplemental material
SHL service changes and data management of variables
Chlamydia and gonorrhoea nucleic acid amplification test (NAAT) uses Roche Cobas from self-sampled urine, vaginal, anal and/or throat specimens. Blood testing uses Roche Elecsys Duo fifth-generation HIV test from self-obtained finger-prick sampling into a microtube vial (400–600 μL capillary blood required). HIV screening is provided by SHL and confirmation testing is referred to clinic-based services. Therefore, only reactive HIV test outcomes are reported in this analysis. If a HIV test result was inconclusive (eg, insufficient or equivocal), a second blood HIV test kit would be offered and dispatched to the user via a specific weblink. This is known as a HIV direct order. Syphilis and hepatitis B and C testing was excluded from this analysis. Results are communicated via an online web portal, text message and/or email (depending on service user preferences) and by phone for reactive blood test results, with linkage into clinic-based services depending on the user preference.
Eligible service users with a positive chlamydia result receive a unique online link to access postal chlamydia treatment through LPOD. Referral to clinic-based services for chlamydia treatment was required for extragenital infection and service users with symptoms until March 2020; subsequently, only those with urgent symptoms and/or more than one STI were referred to clinic-based services. Those who require gonorrhoea treatment are referred to clinic-based services and therefore gonorrhoea treatment outcomes are not available for this analysis.
Methodology
This is a service evaluation of routinely collected SHL clinical service data from 8 January 2018 to 31 March 2022, including completed consultation forms and STI test kit orders. This analysis focuses on HIV, chlamydia and gonorrhoea test outcomes. Table 1 details the data management of variables impacted by changes to the consultation forms since 2019 and provides variable definitions. Positive NAAT result refers to positivity at any of the genital and/or extragenital sites. Chlamydia treatment outcomes were obtained from LPOD prescription data, with date of prescription being used for treatment date in this analysis. As a service evaluation ethical approval was not required.
Analysis
Descriptive analysis is provided for the uptake of each stage of SHL’s clinical care pathway. Binary logistic regression was used to examine the association between explanatory variables and chlamydia and gonorrhoea NAAT results. Insufficient samples and orders without a returned test kit were excluded from the model. Crude ORs and adjusted ORs (aORs) for explanatory variables are provided. Descriptive HIV test outcomes are provided. Analysis was performed on STATA V.17.
Results
During the evaluation period, 1 476 187 orders were completed by 670 293 unique users. Median time for the return of STI kits was 9 days (IQR 6–15 days), and median time from returned sample date to sample processing and result was 2 days (IQR 1–2 days). Median time from STI kit order date to chlamydia treatment prescription was 11 days (IQR 8–18 days); median time from receipt of STI test kit to chlamydia treatment prescription was 2 days (IQR 1–3 days) (missing 331 postal treatment prescription dates). Proportion of returned chlamydia and gonorrhoea NAATs was 79.5% and 67.6% for HIV samples, of all STI kit orders. Proportion of processable NAAT samples (‘sufficient samples’) of returned NAATs was 99% and 98.7% for chlamydia and gonorrhoea, respectively, and 88.2% of returned bloods samples were sufficient for HIV testing (with appended orders). Table 2 provides descriptive outcomes of the clinical care continuum for HIV, chlamydia and gonorrhoea pathways.
Uptake of SHL’s clinical care continuum
Chlamydia and gonorrhoea NAAT positivity was 4.5% and 1.6%, respectively. Chlamydia NAAT positivity was highest in those aged 16–20 years (9.7%) compared with older ages, trans women (7.6%) compared with other genders, black ethnicities (6%) compared with white/mixed/Asian/other ethnicities, the most deprived Index of Multiple Deprivation (IMD) (5.1%), same sex partners (6.4%) and those who collected smartkits (6%) compared with postal kits. Whereas gonorrhoea NAAT positivity was highest in those aged 41 years and older (2.8%) compared with younger ages, trans women (8.1%) vs other gender identities and people with same-sex partners (6.4%).
After adjustment, those with a positive chlamydia test result were: more likely to be cisgender men (aOR 1.31 (95% CI 1.28 to 1.34), p≤0.001), trans women (aOR 2.63 (2.00 to 3.47), p≤0.001), trans men (aOR 1.97 (1.39 to 2.79), p≤0.001), non-binary (aOR 1.39 (1.14 to 1.69), p=0.001) and other gender (aOR 1.70 (1.39 to 2.09), p=≤0.001) compared with cisgender women; more likely to be black (aOR 1.46 (1.43 to 1.49), p≤0.001), mixed (aOR 1.26 (1.23 to 1.30), p≤0.001) and other ethnicities (aOR 1.27 (1.20 to 1.34), p≤0.001) compared with white ethnicity; more likely to have same-sex partners (aOR 1.59 (1.54 to 1.63), p≤0.001) compared with opposite sex partners; more likely born outside the UK (aOR 1.20 (1.17 to 1.22), p≤0.001) and more likely to collect a smartkit compared with postal kit (aOR 1.37 (1.33 to 1.41), p≤0.001) (table 3).
Association between user demographics and OPSS service use and chlamydia outcomes (univariate variate and adjusted logistic regression model, n=1 161 692)
After adjustment, those testing positive for gonorrhoea were more likely to be cisgender men (aOR 1.99 (95% CI 1.90 to 2.07), p≤0.001), trans women (aOR 4.30 (3.24 to 5.71), p≤0.001), trans men (aOR 2.30 (1.32 to 3.17), p=0.001), non-binary (aOR 1.72 (1.37 to 2.16), p=≤0.001) and other gender (aOR 1.38 (1.02 to 1.87), p=0.038) compared with cisgender women; more likely to be black (1.37 (1.31 to 1.44), p≤0.001) and mixed ethnicity (aOR 1.21 (1.15 to 1.26), p≤0.001) compared with white ethnicity; less likely to have only opposite sex partners compared with only same-sex partners (aOR 7.83 (7.50 to 8.17), p≤0.001), both (aOR 3.50 (3.30 to 3.70), p≤0.001) and other partners (aOR 4.47 (3.81 to 5.25), p≤0.001); more likely born outside of the UK (aOR 1.16 (1.12 to 1.20), p≤0.001) and more likely to collect a smartkit compared with postal kit (aOR 1.44 (1.37 to 1.52), p≤0.001) (table 4).
Association between user demographics and OPSS service use and gonorrhoea outcomes (univariate variate and adjusted logistic regression model, n=1 157 780)
Discussion
This is the largest UK analysis of OPSS with nearly 1.5 million test orders across London, over a 4-year evaluation period, with a high proportion of positive chlamydia NAATs among those aged 16–20 years at 9.7%, reflecting the 10% positivity rates seen in the UK national chlamydia screening programme for those aged 15–24 years.7 In 2018, SHL found STI positivity to be 15.2%–16.4% in those aged 16 and 17 years, suggesting positive engagement of OPSS with young people.8
Return rates and sufficient sampling
The 79.5% return rate of chlamydia and gonorrhoea NAATs is higher than those reported in a recent scoping review (between 48.3% and 78.4%).5 The inclusion of processable NAATs with returned STI test kits was 98.7%–99%. The high return rate may be related to how SHL services have been embedded in sexual healthcare pathways over the last 4 years, with clinic-based services actively encouraging asymptomatic sexual health screens via OPSS and service changes during the COVID-19 pandemic influencing health-seeking behaviours.9 10 Preventx have also previously worked with other sexual health testing services and developed methods to encourage return of STI test kits.11
The HIV blood test return rate was 67.6% of STI kit orders and this compares with a HIV sample return rate from all kit orders of 55.7%–60.4% from the national HIV testing service and 55.2% at 56 Dean Street.11–13 In our analysis, 88.2% of returned blood samples and 59.7% of all STI kit orders were sufficient for HIV testing, with appended HIV direct orders. In Birmingham, the return rate of blood samples was 54%; 55% of these returned blood samples were sufficient for HIV testing.14 15 However, Banerjee et al only included the first test kit order per unique user during their 6-month evaluation period in 2017, which limits direct comparison of these figures. Reasons for not returning kits may include difficulty in obtaining sufficient finger prick samples, declining to test or lack of perceived risk.15
Return rates are reported for each testing episode, but the testing pattern for unique users is not considered in these outcomes. For example, SHL users may have tested recently with SHL or elsewhere for HIV and could explain why return rates for HIV blood samples are not as high as chlamydia and gonorrhoea NAATs. Triangulation of online STI testing data with clinic-based sexual health service data and unique users is needed to better understand HIV and STI testing patterns. It is important for future planning of OPSS services to consider the wastage of non-returned blood and NAATs kits. While SHL has the highest return rates, up to 32.3% of blood testing kits and 20.5% of NAATs are not being used. However, this needs to be balanced against the benefits of OPSS. For instance, 26% of users of the UK Health Security Agency's (UKHSA) national online HIV testing service had never previously tested for HIV, and 19.4% of users in our evaluation with either chlamydia or gonorrhoea negative or positive results had only used OPSS services.11
Test result outcomes and associations with positive chlamydia and gonorrhoea test results
SHL positivity rates of 4.5% and 1.6% for chlamydia and gonorrhoea, respectively, are lower than other UK OPSS services (4.4%–8.1%) and clinic-based sexual health services (10.3%–14.4%).5 SHL was an asymptomatic testing service prior to the COVID-19 pandemic and during the COVID-19 pandemic urgent symptoms were still redirected to clinic-based services. These factors may contribute to a lower positivity rate.
High aORs for chlamydia and gonorrhoea positivity in trans women, trans men and non-binary groups in this analysis provide valuable understanding of online STI positivity rates in these groups. To our knowledge, this is the first time STI data have been reported for non-binary people in sexual health testing outcomes in the UK. Previous data from SHL in 2019 found a lower positivity rate for chlamydia (4.8%) and gonorrhoea (3.4%) when trans women, trans men and non-binary groups were grouped together, but this was during the early years of SHL.16 Comparisons with clinic-based sexual health services and other health services would be helpful to understand if higher aOR are due to increased incidence in these groups, or possibly concerns regarding confidentiality and stigma in clinic-based services. However, the absolute numbers are small and therefore caution is required when interpreting these results. Adjusted odds showed a reduced odds of chlamydia and gonorrhoea positivity with increasing age, and those from less deprived IMD areas, the latter reflecting chlamydia positivity association with deprivation in England.17
A higher positivity rate in those taking smartkits may be related to symptoms or behaviours leading to seeking care from a clinic-based sexual health service before being redirected to OPSS. Increased adjusted odds for chlamydia and gonorrhoea positivity were observed with a higher number of test orders. This might be related to pre-exposure prophylaxis (PrEP) users having unlimited access to STI kit orders since March 2021, but a limitation of this data is not having PrEP history available. Triangulation with data on PrEP use and OPSS would be helpful to better understand this relationship.
The odds of test positivity varied according to use of OPSS-only or both clinic-based and OPSS. Gonorrhoea positivity was lower in those only using OPSS (aOR 0.71; 95% CI 0.67 to 0.75) compared with both OPSS and clinic-based services, which may reflect how symptoms are triaged in OPSS and clinic-based services.
Some major limitations to the logistic regression model include the lack of data on sexual partner number, PrEP use, symptoms and condomless sex. Also, non-UK born does not account for difference in Anglosphere countries as the SHL website is only available in English, but these data may also reflect difficulty in those non-UK born in accessing clinic-based health services or fear in doing so.
HIV testing results
HIV reactivity at 0.3% is lower than the national HIV self-sampling service (0.8%–1.05%), using the same laboratory services (Preventx) from 2015 to 2019.11 13 However, the national HIV self-sampling service targeted high-risk groups. False positives are likely to be present in lower prevalent populations, but confirmatory outcomes were not available for this analysis. Previously, SHL reported a HIV reactivity rate of 0.97% for unique users from 2018 to 2019, but reactivity by STI test kit orders and testing episodes was not available for comparison.18 Birmingham’s OPSS found a reactivity rate of 1.5% and a positivity rate of 0.02% from sufficient HIV samples returned from first STI test kit orders from unique users during their analysis period in 2017.15 In a randomised controlled trial of OPSS services, there were no HIV confirmations and reactivity was not reported.19 More data on BBV outcomes from OPSS would enhance our understanding of how to best use OPSS BBV testing.
Treatment
Treatment outcomes demonstrate a high uptake of remote chlamydia prescribing compared with other OPSS services (56.7% with SHL vs 46% in Birmingham).2 Follow-up of positive chlamydia cases found 39.7% had accessed chlamydia treatment elsewhere, meaning 96.6% of SHL users had chlamydia treatment outcomes, compared with 82% of chlamydia test positive service users in Birmingham.2 This could be due to several factors; the need for remote healthcare access during the COVID-19 pandemic and digital tracking of SHL service users who are seen in routine sexual health services in London for treatment. There have also been changes to the criteria for those eligible for remote treatment over time; inclusion of treatment for extragenital chlamydia and treatment of some symptomatic service users. Time from test kit order to prescription was 11 days, but only 2 days from when the test kit was returned. However, the time taken for users to start treatment, taking into account postal delivery times, is unknown and represents a limitation.
Further limitations
This is a retrospective evaluation of service data, over a 4-year period. The service has undergone several changes during this evaluation period, including changes to the consultation questions, expanded access (eg, increasing the number of test kit orders available in some boroughs, unlimited test kit orders for those taking PrEP and widening access to symptomatic users and STI contacts) and the introduction of novel services (eg, contraception provision, not included in this review). These changes may have influenced service use. While we adjusted the model for major service changes, this analysis does not review STI testing rates over time to determine the impact of these service changes. Also, it was outside the scope of this evaluation to review the user demographics of non-returned or insufficient samples. Comparisons with other UK OPSS are limited due to the lack of evaluation data and differences in populations and services. Therefore, caution is needed when comparing service outcome data.
The Genitourinary Medicine Clinic Activity Dataset (GUMCAD) codes, used for national surveillance, were not provided for this evaluation. Despite the absence of GUMCAD data, there are limitations due to the lack of standardised data definitions for process outcomes in OPSS evaluations.20 For example, this includes drop-off rates for consultation forms and STI test kit orders, return rates and sufficient samples for testing. Lastly, we were unable to compare the data with clinic-based services. Difficulties arise due to the use of different patient identifiers, which prevents us from tracking users between clinic-based and OPSS services.
Next steps and conclusion
Our evaluation has highlighted several areas for SHL to address. There is a need to improve equity of access across ethnicities. Additionally, it is important to review the lower positivity rates and low blood sample return rates. Improved data definitions for OPSS service outcomes would support future evaluations. Lastly, further work is needed to combine clinic-based services with OPSS data to truly understand STI testing uptake in London.
This is the largest analysis of OPSS outcomes in UK STI testing services for chlamydia, gonorrhoea and HIV, covering an extended evaluation period. These data demonstrate the occurrence of STI testing in populations who have not previously accessed clinic-based sexual health services and provide detailed information on the increased odds of chlamydia and gonorrhoea positivity among trans or non-binary individuals.
Data availability statement
Data may be obtained from a third party and are not publicly available. Data were provided by Preventx with permission from SHL’s data controller.
Ethics statements
Patient consent for publication
Ethics approval
This project was deemed a service evaluation and ethical approval was not required.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Handling editor Nadja A Vielot
X @jogibbs76
Contributors VT designed, supported data acquisition, analysed and drafted the manuscript. JS and AT led on the data acquisition. SLD and AMK supported data acquisition. SLD, AT, AH, JG, FB and AS supported the design, analysis and drafting of the manuscript. AS conceived the evaluation. All authors supported revision of the manuscript. VT is the guarantor.
Funding VT received partial funding from City of London to support her work on this analysis.
Competing interests VT received supplementary funding from City of London to undertake the analysis. However, City of London had no role in the design of the evaluation. No other competing interests were declared.
Provenance and peer review Not commissioned; internally peer reviewed.
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